1. Field of the Invention
The present invention relates to a multiple-input multiple-output antenna module, and more particularly, to a hybrid multiple-input multiple-output antenna module and a system of using the same.
2. Description of Related Art
The wireless LAN or 802.11a/b/g/n access-point antenna of the related art is almost of an external antenna structure. Common dipole antennas have a plastic or rubber sleeve covering thereon. In general, the dipole antenna is a single-band antenna for 2.4 GHz operation or a dual-band single-radio antenna for 2.4/5 GHz operation. The height of the dipole antenna is triple the thickness of the wireless broadband router/hub device, and one part of the dipole antenna is arranged on a side of the router and the rest of the dipole antenna is protruding from the top of the access-point or router enclosure. However, the protruded part of the dipole antenna can easily be vandalized by an outside force and also occupies space, which deteriorates the aesthetic appeal of the product, especially for the multi-antenna system.
Conventional dual-band single-radio antenna applied to 2.4/5 GHz wireless LAN or 802.11a/b/g/n has only one RF signal feeding port, thus two conductive copper tubes and an extra diplexer need to be used in order to achieve 2.4/5 GHz concurrent dual-band operation. However, the cost would be increased and the whole system loses extra gain or power due to the design of the conventional dual-band single-radio antenna.
Moreover, the related art provides another dual-band cross polarization dipole antenna that discloses a dual-antenna system. The dual-antenna system has two dual-band dipole antennas to generate two frequency bands for 2.4/5 GHz operation. However, the dual-antenna structure is of a stacked structure, thus the height of the whole antenna structure is high.
Furthermore, the enterprise access-point antenna or the router is usually installed on a ceiling. Thus, the downlink and uplink qualities would be directly affected by the antennas radiation-pattern coverage. Because the operating frequencies in 5 GHz band are larger than the operating frequencies in 2.4 GHz band, the path loss of a 5 GHz antenna is larger than the path loss of a 2.4 GHz antenna. Therefore, the gain of a 5 GHz antenna needs to be larger in order to compensate high path loss in 5 GHz band.